<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
  <script src="https://apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js">
  </script>
</head>

<body>
  <!-- jquery里面包含很多js
函数 -->
  <a href="#" id="te">点我</a>
  <script>
    var aa = document.getElementById('te')
    //$().(方法)
    //选择器,因为是id选择器，所以美元符后面括号里面要写#
    $('#te').click(function () {
      alert('hello   jquery ')
    })
  </script>
</body>

</html>